Tray carrying-in starting mechanism for disk drive

ABSTRACT

In order to provide a tray carrying-in starting mechanism for a disk drive, which is simple and reduces a load at the start of carrying-in of a tray, and in which a tray carrying-in action is started by pushing a tray having been carried out to a disk exchange position, the starting mechanism comprises a projection provided on a rear end portion of the rack with a predetermined spacing from a tooth at a rear end of the rack, an untoothed portion provided on an outer periphery of the gear that meshes with the rack, and a cam groove formed on the outer periphery of the gear to allow the projection to slide over a predetermined extent and to engage therewith, the projection engages with the cam groove when the tray is carried out to the disk exchange position, and the tray can be retreated a predetermined distance without rotation of the gear when the tray is pushed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a tray carrying-in starting mechanismin a disk drive for reproduction/recording of optical disks,magnet-optical disks, such as CD, DVD, MD, etc.

2. Related Art

A disk drive for reproduction of CD, DVD, etc. comprises a tray thatplaces thereon a disk to carry in and out the same, a drive unit forrotation of a disk, a pickup, and a feeding device to move the pickup.The respective constituent parts are provided with motors needed formovements thereof and can perform necessary movements through therespective motors.

A tray that places thereon a disk to carry in and out the same from adisk drive body is driven by a motor, a gear meshes with a rack that isprovided on a side of the tray, and the gear is rotatively driven by amotor. In the case where a tray presents in a disk exchange position isto be carried into a disk drive, an operating button may be made ON todrive the motor but mounting the operating button on a front panel givesrise to a need for a substrate and a switch, which results in anincrease in cost.

Hereupon, in some cases, when a tray is pushed by a hand to retreatslightly, a position of the tray is detected and a motor is started tocarry the tray into a disk drive. However, such tray carrying-inmechanism is constructed such that when a tray is caused to retreat, agear meshing with a rack is rotated and the gear interlocks with a gearmounted to a spindle of a motor. Accordingly, a load of a certainmagnitude acts in retreating the tray to give rise to a weight, thusworsening the operability of the tray.

For example, “disk recording/reproduction apparatus” according toJP-U-3088851 is known as a tray carrying-in mechanism constructed toretreat with a light push force in order to reduce a load on a tray.With such apparatus, a rail is provided in a tray accommodating sectionin a disk drive body, a rack is provided on a tray, a rear end portionof the rack is untoothed, and a rack piece is mounted slidably on therack in a manner to overlap the untoothed portion. Leaf springs aremounted on both sides of a rear portion of the tray whereby the tray canbe pushed with a slight force, which counteracts the bias of the leafsprings, because the rack and a pinion connected to a drive shaft of themotor are out of mesh with each other when the tray is to be pushed in.

However, such disk recording/reproduction apparatus needs a rack piece,the rack piece must be mounted overlappingly on a rack to be slidablethereon, and the number of parts and man hour in a work of assemblingthe rack piece are increased. Further, a mechanism is provided such thata slot is formed to allow a tray piece to slide in a predetermined range(L) at the time of carrying-in and carrying-out of a tray, and the traypiece collides against and interlocks with a pin provided upright on thetray, but collision noise is generated whenever ends of the slot collideagainst the pin. Occasionally, the rack piece are increased in slideresistance due to some reason to have the apparatus failing to function.

Also, while the leaf springs are used in the disk recording/reproductionapparatus to function to position the tray as carried out, there is aneed for a unit to accommodate therein the leaf springs and the railbecause the leaf springs are moved together with the tray. As a result,the apparatus is increased in widthwise dimension. Further, an amount,by which the tray projects, and timing, at which the rack separates fromthe pinion, are varied depending upon positions, in which the leafsprings are mounted, so that individual apparatuses give rise todispersion to be degraded in quality. Further, since the leaf springscome into frictional contact with and slide on the rail when moving atthe time of carrying-in and carrying-out of the tray, additional poweris needed.

In this manner, a tray carrying-in starting mechanism in conventionaldisk drives involves the problem described above. It is an object of theinvention to solve such problem and to provide a tray carrying-instarting mechanism that is very simple and reduces a load at the startof carrying-in of a tray.

SUMMARY OF THE INVENTION

In order to attain the object, the invention provides a tray carrying-instarting mechanism, in which a tray carrying-in action is started bypushing a tray that is carried out to a disk exchange position, for adisk drive, in which a gear rotatively driven by a motor meshes with arack provided on a side of the tray, the starting mechanism comprising aprojection provided on a rear end portion of the rack with apredetermined spacing from a tooth at a rear end of the rack, anuntoothed portion provided on an outer periphery of the gear that mesheswith the rack, and a cam groove formed on the outer periphery of thegear to allow the projection to slide over a predetermined extent and toengage therewith, and wherein the projection engages with the cam groovewhen the tray is carried out to the disk exchange position, and the traycan be retreated a predetermined distance without rotation of the gearwhen the tray is pushed.

The projection is provided on the same plane as that of the rack andprojects to a large extent in the same direction as that of teeth of therack, so that the projection can surely engage with the cam groove in alimited space without generating slip.

When the projection collides against a rear end of the cam groove, thetray is carried out, and when the tray reaches the disk exchangeposition, the gear is reversed just before the projection comes intocontact with a forward end of the cam groove. Accordingly, the diskexchange position of the tray is fixed, and when the rack is pushed, therack can be retreated in a range of the cam groove without meshing withthe gear. Accordingly, since the gear does not rotate in the meantime, aforce required for pushing the tray is small and an improvement isachieved in operability.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a plan view showing a state, in which a tray is carried out,in a disk drive provided with a tray carrying-in starting mechanismaccording to the invention;

FIGS. 2(a) and 2(b) are a plan view and a right side view, respectively,showing a state, in which carrying-out of a tray is completed in thetray carrying-in starting mechanism according to the invention;

FIGS. 3(a) and 3(b) are a plan view and a right side view, respectively,showing a state just before carrying-in of a tray is started; and

FIGS. 4(a) to 4(d) is plan view, respectively, showing a state, in whicha gear and a rack mesh with each other in respective stages.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

An embodiment of the invention will be described below in detail withreference to the drawings. FIG. 1 is a plan view showing a disk driveprovided with a tray carrying-in starting mechanism according to theinvention, in a state, in which a tray 1 is carried out and opened. Thetray 1 is formed on an upper surface thereof with a disk placed surfacethat is circular in shape and recessed to be shallow, and a disk isfitted and set on the disk placed surface. Also, a rack 2 is provided ona side of a lower surface of the tray 1 in a longitudinal direction, anda substantially L-shaped guide groove 3 is formed along the rack 2.

A gear 4 rotatively driven by a motor 6 meshes with the rack 2, and thegear 4 is rotatively driven to carry the tray 1 into and out of a diskdrive. A cam-rod projection 5 provided on and projecting from a cam rod10, which is arranged in a front part of a cam unit to be able toreciprocate laterally, is loosely fitted into the guide groove 3. Theguide groove 3 comprises a longitudinal groove portion 7 formed inparallel to the rack 2, a transverse groove portion 8 formed at a rightangle relative to the rack 2, and a corner groove portion 9 formedobliquely between the longitudinal groove portion 7 and the transversegroove portion 8. Also, a rear end portion of the longitudinal grooveportion 7 extends slightly offset with a curved portion midway.

Accordingly, when the tray 1 is carried out to advance, the tray 1 stopsin a location where the cam-rod projection 5 loosely fitted into thelongitudinal groove portion 7 comes to the curved portion. Also, whenthe tray 1 is carried in to retreat, the tray 1 stops in a locationwhere the cam-rod projection 5 loosely fitted into the longitudinalgroove portion 7 comes to the corner groove portion 9. That is, when thecam-rod projection 5 moves along the guide groove 3, the cam rod 10 ismoved, of which movement is detected to cause the tray 1 to stop.

By pushing an eject button provided on a front panel, the motor 6 isstarted to rotate the gear 4 to forward the rack 2 and to carry out thetray 1 to stop the same in a disk exchange position. On the other hand,when the tray 1 present in the disk exchange position is to be carriedto a disk reproduction position, or a disk standby position in the diskdrive, a tip end of the tray is pushed to retreat whereby the motor 6 isstarted detecting such movement of the tray 1 and the gear 4 is rotatedto feed the rack 2.

FIGS. 2(a) and 2(b) show an embodiment of the tray carrying-in startingmechanism according to the invention. The figures show a state, in whichcarrying-out of the tray 1 is completed and the tray is present in thedisk exchange position, and in which the rack 2 meshes with the gear 4to be carried out by virtue of rotation of the gear 4, and teeth of therack disappear in a predetermined position on a rear end of the rack tobe out of mesh with the gear 4.

A projection 11 is provided on the same plane as that of the rack 2 in arear part of the rack 2 to be distant a predetermined spacing from atooth at the rear end of the rack to project toward the gear 4. Anuntoothed portion 4 a is formed on an outer periphery of the gear 4, anda cam groove 12 is formed by cutting out that part of the untoothedportion 4 a, which is sector-shaped in a circumferential direction andhas a predetermined width. The projection 11 and the cam groove 12 arepositioned in a manner to engage with each other in synchronism withtiming, at which the gear 4 is rotated to carry out the tray 1 and ismade out of mesh with the rack 2 and the rack 2 separates from the gear4. The tray 1 stops when the cam groove 12 engages with the projection11 and the gear 4 is rotated slightly. At this time, the projection 11contacts with a rear end 13 of the cam groove 12 (see FIG. 2(a)).

FIGS. 3(a) and 3(b) show the case where the tray 1 is carried into thedisk drive. The projection 11 is fitted into the cam groove 12 of thegear 4, and a distance L with the projection 11 loosely fitted isprovided between the projection 11 and the rear end 13 of the cam groove12. By pushing the tray 1 in a direction indicated by an arrow, that is,in a direction toward a body of the disk drive, the tray 1 is caused toretreat as far as the projection 11 is present in an extent of thedistance L but the gear 4 is not rotated, and when the tray retreats bythe distance L, the projection 11 collides against the rear end 13 tostart rotation of the gear 4. Accordingly, it suffices that a load, withwhich a finger pushes the tray 1 to carry the same into the disk drive,be very small. The gear 4 meshes with the rack 2 at the same time whenthe gear 4 begins rotation, and the motor 6 is started to rotativelydrive the gear 4, thus enabling feeding the rack 2.

FIGS. 4(a) to 4(d) show the relationship between the gear 4 and the rack2. FIG. 4(a) shows carrying-out of the tray 1, in which the gear 4meshes with the rack 2, and the rack 2 and the tray 1 are carried outand moved with rotation of the gear 4. FIG. 4(b) shows a state, in whichthe tray 1 is carried out to reach the vicinity of the disk exchangeposition and the gear 4 separates from the rack 2. That is, when thetooth at the rear end of the rack reaches the untoothed portion 4 a,meshing of the gear 4 and the rack 2 is terminated and the projection 11provided at the rear end portion of the rack engages with the cam groove12 that is formed on the outer periphery of the untoothed portion of thegear 4.

FIG. 4(c) shows a state, in which the projection 11 engaging with thecam groove 12 is pushed out upon rotation of the gear 4 and the rack 2and the tray 1 stop in a predetermined disk exchange position. Whenrotation of the gear 4 is stopped, the gear 4 is reversed to stop justbefore a forward end of the cam groove 12 comes into contact with theprojection 11 (FIG. 4(d)). That is, the projection 11 collides againstthe rear end 13 of the cam groove 12 to be pushed out, and the gear isreversed an angle corresponding to an extent of the cam groove 12 tostop.

The rack 2 and the gear 4 are molded from a resin material, and moldingis easy even when a gear comprises the untoothed portion 4 a and the camgroove 12. Also, the invention is applicable to a disk drive with a diskexchanger, which comprises a plurality of trays.

As described above, with the tray carrying-in starting mechanism of thedisk drive according to the invention, in case of pushing a tip end ofthe tray to retreat the tray when the tray is to be carried in, the gearis not rotated but stopped until the projection collides against therear end of the cam groove, and the gear mechanism that rotativelydrives the gear by means of a motor is not actuated, so that a loadacting on the tray is small and the tray can be pushed with a lightforce to lead to an improvement in operability of the tray.

Also, since the projection provided in the rear part of the rack is onthe same plane as that of the rack and projects in the same direction asthat of the teeth of the rack, molding is facilitated and no additionalspace is needed.

Further, it suffices to provide the untoothed portion on a part of thegear and to form the cam groove, but any specific parts are not neededand the number of parts is the same as that in conventional traycarrying devices. Further, only by restricting a rotating angle of thegear, a disk exchange position, in which the tray is carried out, can befixed.

1. A tray carrying-in starting mechanism for a disk drive, in which agear rotatively driven by a motor meshes with a rack provided on a sideof a tray, and a tray carrying-in action is started by pushing the trayhaving been carried out to a disk exchange position, the startingmechanism comprising a projection provided on a rear end portion of therack with a predetermined spacing from a tooth at a rear end of therack, an untoothed portion provided on an outer periphery of the gearthat meshes with the rack, and a cam groove formed on the outerperiphery of the gear to allow the projection to slide over apredetermined extent and to engage therewith, whereby the projectionengages with the cam groove when the tray is carried out to the diskexchange position, and the tray can be retreated a predetermineddistance without rotation of the gear when the tray is pushed.
 2. A traycarrying-in starting mechanism for a disk drive according to claim 1,wherein the projection is provided on the same plane as that of the rackand projects to a large extent in the same direction as that of teeth ofthe rack.